Abstract

A negative energy balance (NEB) attributed to sugar and lipid metabolic disorders are common in periparturient cows. The relationship between periparturient disorders and amino acid metabolism is unclear. The present study was aimed to observe the kinetics of blood free amino acids healthy periparturient cows simultaneously with the concentrations of biochemical constituents in plasma. The changes in the concentrations of plasma biochemical constituents and blood free amino acids were monitored in healthy periparturient cows. There were three types of amino acid; a group of amino acids (Val, Leu, Ile, Trp, Thr, Arg, Lys, Tyr, Ala, Pro, Asn, Orn) whose blood concentrations decreased because their consumption is accelerated under periparturient energy-shortage state, a group of AAs (Gly, Ser) whose concentrations increased because they are mobilized to compensate for periparturient energy shortage, and a group of amino acids (Glu, Gln) that are taken into the mammary gland tissues and mobilized from the start of lactation after delivery. The blood free amino acid concentrations in periparturient cows indicated the various kinetics of amino acid concentration corresponding to changes in energy generation. Analysis of amino acid metabolism should be entertained in the pathogenesis of NEB-related periparturient disorders.

Key words: Cow, serum free amino acid concentration, periparturient, metabolism of amino acid.

Abbreviation

AA, Amino acid; Ala, alanine; ALB, albumin; Arg, arginine; Asn,asparaginic acid; Asp, asparagines; AST, asparate aminotransferase; BHB, β-hydroxybutyrate; EAA, essential amino acid; FAAs, free amino acids; FAs, fatty acids;FFAs, free fatty acids; GL, glucose; Gln, glutamic acid; Glu, glutamine; Gly, glysine;His, histidine; Ile, isoleucine; Leu, leucine; Lys, lysine; Met, methionine; Orn,ornithine; Phe, phenylanine; Pro, proline; Ser, serine; T-AA, total amino acid; TChl,total cholesterol; T-EAA, total essential amino acid; Thr, threonine; T-NEAA, total non-essential amino acid; TP, total protein; Trp, tryptophane; Tyr, tyrosine; Val, valine; γ-GTP, γ-glutamyl transpeptidase.